Improvement in lifting-jacks



UNITED STATES PATENT OEEIoEc JOHN T. HAMILTON, OF BOONE COUNTY, AND EZRAF. OONNER, OF DEOATUR, INDIANA 5 SAID GONNER ASSIGNOR TO SAID HAMILTON.

IMPROVEMENT IN LIFTING-JACKS.

Specification forming part of Letters Patent No. 144,977, dated November25, 1873 application tiled September 24, 1873.

To all whom t may concern: A

Be it known that we, Jol-IN T. HAMILTON, of Boone county, and EZRA F.CONNER, of Decatur, in the State of Indiana, have invented certain newand useful Improvements in Lifting-Jack; and do hereby declare that thefollowing is a full, clear, and exact description thereof, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon, making a part of this -the machine, all as more fullyhereinafter set vforth and claimed.

In order to enable others skilled in the art to which our inventionappertains to make and use the same, we will now proceed to describe itsconstruction and operation, referring to the annexed drawing, whichrepresents a perspective view of our improved lifting-jack.

A A represent two legs, pivoted together at their upper ends by a bolt,a. This bolt passes through and pivots the lever B between the two legsA A, as shown. To the lever B is hinged a bar, C, by means of two curvedplates, which are iirmly fastened, one on each side, at the end of thebar C, and the projecting ends of said plates are pivoted to the leverB, one on each side thereof. These curved plates guide the bar Cproperly while depressing the lever, and add strength to the machine.

The bar C is provided with a series of ratchetteeth, b b, cut in itsunder side, and passes in between the legs A A. D represents a rod, oneend of which is attached to the bolt a on one side of the machine, andthe lower end of said rod is bent at right angle and fastened by ascrew, d, to the front side of the leg on the other side of the machine.The ratchet-bar O passes between this leg and the rod D, and theratchet-teeth b b catch on the horizontal part of said rod, holding thelever in position after the article has been raised by the same.

In the patent above referred to, a short rod was used with both endsbent at right angles and fastened in one leg of the machine. Thisarrangement threw the whole strain from the article lifted through theratchet-bar to one side of the machine, and made it difficult to yhandle, and liable to tip over. By our present arrangement of the rod D,it will be seen that the strain is equal on both sides, thus steadyingand strengthening the machine.

Having thus fully described our invention, what we claim as new, anddesire to secure by Letters Patent, is-

' In a lifting-jack, the combination of the lever B, rod D, the ends ofwhich are secured to the sides of the legs A A, and the rack-bar C, allsubstantially as and for the purposes set forth.

In testimony that we claim the lforegoing we have hereunto set our handsthis 7th day of August, 1873.

JOHN T. HAMILTON. EZRA F. CONNER.

VVit-nesses FRANK M. DoWDEN, H. H. WooLLEv.

